//
// Created by Programmer on 2021/11/23.
//
//#include <stdio.h>
//
//int main() {
//    int day = 9;
//    int cur_day_count = 1;
//    int pre_day_count;
//    while (day > 0) {
//        pre_day_count = (cur_day_count + 1) * 2;
//        cur_day_count = pre_day_count;
//        day--;
//    }
//    printf(" %d\n ", pre_day_count);
//}




